Preheat oven to 180'C.
Dice the cold butter and rub into the flour until fine breadcrumbs are formed. Add the sugar and mix through. Make a well in the centre and add the egg yolk. Bring the mix together until a dough is formed. Wrap in clingfilm and place in the fridge for 30 minutes.
After the dough has rested, remove from the fridge and roll out on a lightly floured surface to the thickness of 3-5mm. Roll it back over the rolling pin to enable you to lift the whole pastry up and line tart case. Push the dough into the sides of the tart case using a piece of excess pastry.
Pierce the base with a fork then line with clingfilm and fill with baking beans. Blind bake for 25 minutes. Remove from the oven, remove the baking beans and return the shell to the oven for 10 minutes. Remove and lightly egg wash all over. Then return to the oven for 10 minutes. Trim the sides with a knife and use a pastry brush to clean away any unwanted crumbs.
Break the chocolate into small pieces and put in a bowl. Bring the milk and cream to the boil and pour over the chocolate. Whisk until chocolate has melted. Slowly add the egg yolks, whisking constantly.
Pour into the blind baked shell and bake in the oven until cooked. If the centre wobbles when the case is tapped then return to the oven until completely set. Remove from the oven and allow to stand for 30 minutes before serving.
Serve hot or cold.
Whisk the cream to soft peaks, sieve in the icing sugar and fold in the marmalade. Using a hot spoon place a quenelle of cream next to the tart.
«To vary the flavour you can add an alcoholic liqueur or orange zest to the filling before baking or even sprinkle some chopped hazelnuts on top. »